In reality the CPCP production started in 1997. Platinum Ronde Louis Cartier from 1997 exists. This one, both movement and case are from 1998. In 1999 the watch was updated with a full guillloché dial, Bréguet hands and 437MC movement.
Although from the Tortue family, it’s a Cartier Dauphine from 1978, made by Ebel in Switzerland. Of course the dial is white enamel! Relatively rare watch.
These are the initials of the case manufacturer that you can see inside the diamond shaped punch. I sent an email to French customs to find out who was hiding behind this mark, but no answer.
Here is some informations about the Tonneau: (please note that this website is still under construction!) As you can see the Tonneau was made in France until 2005.